(Reuters) - Following are main developments after a massive earthquake struck northeast Japan on Friday and set off a tsunami.
Death toll expected to exceed 10,000 from the quake and tsunami, public broadcaster NHK says. About 2,000 bodies found on two shores of Miyagi prefecture, Kyodo news agency reports.
Japan battles to prevent nuclear catastrophe. A hydrogen explosion jolts the No. 3 reactor of the Fukushima Daiichi nuclear power plant, 240 km (150 miles) north of Tokyo. Operator Tokyo Electric Power Company (TEPCO) (9501.T) says 11 people were injured.
Chief Cabinet Secretary Yukio Edano says the core container at the reactor is intact and the explosion is unlikely to have produced a large escape of radioactivity.
Before the blast, officials said 22 people had suffered radiation contamination. Up to 190 may have been exposed.
Experts pursue efforts to cool down three reactors at the Fukushima Daiichi plant. Experts say the use of seawater in this operation is unprecedented.
Nuclear safety agency rates the incident a 4 on the 1 to 7 International Nuclear and Radiological Event Scale, less serious than Three Mile Island, a 5, and Chernobyl at 7.
U.S. warships and planes helping relief efforts have moved away from Japan's Pacific coast temporarily because of low-level radiation.
Authorities have set up a 20-km (12-mile) exclusion zone around the Fukushima Daiichi plant and a 10-km (6 mile) zone around Fukushima Daini.
Strong aftershocks persist in the stricken area.
About 450,000 people evacuated nationwide in addition to 80,000 from the exclusion zone around the nuclear power plants. Almost 2 million households are without power in the freezing north and about 1.4 million households have no running water.
Reactor operator says rolling blackout to affect 3 million customers, including large factories, buildings and households.
Japan's Nikkei share index falls more than 6 percent, dragging European stocks to their lowest in three months.
The Bank of Japan (BoJ) offers to pump a record $85 billion into the banking system.
Credit Suisse estimates the loss at between 14 trillion yen and 15 trillion yen just to the quake region.